Cytology and Movements of the Cyanophycee. 319 
tention that they arise from amceboid bodies in a broken 
cell is not to the point, because they often arise in unbroken 
end cells. Further, Hansgirg considered that the long hair- 
like appendages along the sides of Cylindrospermum were of 
the same nature as the hair-like organs of Oscillaria. But 
since these long processes only appear upon the sides of the 
heterocyst and spores, both of which have strongly thick- 
ened walls, it can scarcely be thought that any parasitic 
organism would penetrate these, and not be found upon the 
thinner-walled vegetative cells. I therefore placed some of 
these filaments in a live-box and kept them under continuous 
observation until these hair-like organs were completely 
formed, which usually consumed from one to three hours, 
according to the strength of the culture and other condi- 
tions involved. Observation was continued for several days, 
and I was rewarded many times by being able to trace the 
gradual development of these so-called parasitic growths 
from the protoplasm of the end cells, noting them in all 
stages of their growth from small swellings to the full- 
grown hairs. When a trichome is broken across, the final 
cell of each broken end exhibits the normal structure (Fig. 
39). Gradually the chromatin of the central body becomes 
diffused and the free end bulges out, on account of the tur- 
gor and relieved pressure from the other cells, on one side 
(Fig. 33). As this proceeds, small finger-like processes 
begin to appear as small swellings over the free surface of 
the cell. These gradually grow out until they become eigh- 
teen or twenty times as long as broad. In their younger 
condition, they take the stains in the same manner as the 
protoplasm of the end cell, but gradually they become more 
impervious to these stains and react in the same manner as 
the cell walls, except for the thin protoplasmic continuation 
into their lumen. Thus it will be seen that they slowly 
harden into a cell wall by the deposition of some substance 
which no longer takes the stain as the softer protoplasm 
does. They gradually assume the reaction of cellulose. 
